Quiz: How well can you use a map and compass?

EVERY FIRST CLASS Scout can compute a bearing from a map and follow it on the ground. But can he correct his compass for magnetic declination? Triangulate his position on a map? Interpret topographic dangers like falls and canyons?

Take this quiz and see how much you and your Scouts know about wilderness navigation. You’ll need a compass and pencil to do some of the problems. Note: An incorrect question on a camping quiz is no big deal; one wrong compass bearing, however, will get you lost!

Choose the best answer. Some questions may have more than one right answer.

This is from the NOAA website. There is similar information on the REI website and other sites. Google “compass southern hemisphere” if you aren’t convinced.
For a compass to work properly, the compass needle must be free to rotate and align with the magnetic field. The difference between compasses designed to work in the northern and southern hemispheres is simply the location of the “balance”, a weight placed on the needle to ensure it remains in a horizontal plane and hence free to rotate. In the northern hemisphere, the magnetic field dips down into the Earth so the compass needle has a weight on the south end of the needle to keep the needle in the horizontal plane. In the southern hemisphere, the weight needs to be on the north end of the needle. If you did not change the weight, the needle would not rotate freely, and hence would not work properly.

Not a stupid answer at all. Compass needles are balanced for the area they are to be used. Most compasses that are balanced for the northern hemisphere and won’t work well in the southern. The reason is the closer to magnetic north, the greater the pull downward of the needle toward the ground.The “Global” compasses are an exception but are more expensive then standard backpacking compasses.

Actually, the earth’s magnetic field lines tend to dive into the ground toward the pole, so compasses designed for the northern hemisphere have extra weight on the south end of the needle to compensate so the needle stays level. That “northern”compass needle in the southern hemisphere would not be level because the extra south end weight would be on the wrong needle end since the field lines would dive toward the south pole. It will work if you can tilt the compass so the needle does not scrape the housing and can rotate freely.

I looked carefully at the answer sheet for number 16 and did some poking around on the internet. While the needle will want to point North, the needle will also want to point up or down (the magnetic field is 3D) Compass manufacturers divide the world into 3-5 “Needle balance zones” and change the center of mass of the needle to compensate, so a compass needle remains more or less level within a zone. If you get too far out of the zone for your compass, the needle will drag on the enclosure and the compass won’t work because the needle needs to swing freely,.

Note, I am not sure if this would apply on a ship’s compass. There may be other tricks used there.

You always need to be sure that the needle is turning freely no matter where you use it. Tilting the compass is normal anywhere. I don’t see why this is considered making the compass work ‘differently’.

There is a small dot of paint underneath the needle to give proper balance. The dot is a different size in the southern hemisphere, because the Earth’s magnetic field is not a perfect sphere. If you use a North American compass south of the Equator, one end of the needle will drag on the capsule. The answer is correct.

Q16 is a good question from the point of view that it make the student think about how the compass really works……like “The compass doesn’t really point to the magnetic North pole but rather aligns itself with the magnetic flux in the area you are in”..
This is information that should be covered in the classroom. and not “taught” in the quiz.
From a practical stand point, I had my compass (purchased in California ) in Tonga several years ago and it worked just fine.
. Given the attention this question(Q16)has driven it in itself is a good learning tool.

Just a reminder to orient map and compass while NOT on or near metal such as the bolts that hold many picnic tables together as this can effect the compass operation. Also when setting up a compass course I always “start” at the finish and make the compass think it is pointing south to get the direction to write down for the course to follow.

Great quiz, which I plan to use in conjunction with my Hiking Meritbadge course. I would agree some of the questions are tricky, and it would be great to have an explanation in the answers to help understanding.

Very disappointed again that I can not just get the answer with a brief explanation if necessary. More questions on the website and different option for answers (question7 for example). Q 16 , I cannot even figure out what your answer is and I question what I think you are saying. Why not put the quiz in the mag and the answers on line.?

Good points by all – good refresher, downloadable .pdf would be excellent, definitely check the answer on number 16 – that sounds sort of silly to me. Great article – will use at Troop meeting. Thanks!

Okay, plausible explanations on the compass needle weighting, but I have never heard of that even with 21 years in the Army carrying a compass. Maybe ours were just good and didn’t care where they were in relation to the equator! The ring that floats in a good lensatic compass has quite a bit of play up and down, so maybe it doesn’t mind diving down, but you would think the Army would have mentioned it in their infinite wisdom – I don’t recall ever seeing that on ein the book.

Good point, John. Army style lensatic compasses have thicker compartments compared to orienteering compasses. I personally recommend orienteering compasses for Scouts, as the tranparent base plate allows them to determine bearings from maps more easily than the lensatics. The lensatics can give a slightly more accurate field bearing, but for all around usefulness, the orienteering compass is in my experience, a better choice.

Steve, point taken – I agree. I carry/use a military lensatic because it is very durable and accurate, but also because I have carried it for work for so many years – it is what I have the most experience with. But I teach Scouts on orienteering-style compasses – cheaper to buy (low-end but good compasses) and easier to use, especially for beginners.

Question 9 can be answered without a compass.
From the corner just West of pt C to the corner about South of point A is 315 degrees. Pt. A is a little north so the answer is obvious.

More explanation.
A line from the SE corner of a grid to the NW corner would be half way between 270 and 360, or 315 degrees. Imagine or draw the 315 degree line and it is obvious that C to A is a little greater.

Doesn’t a compass work anywhere in the world unless there is something causing a deviation?

You said the safest way from point B to point E would be take a bearing on creek and follow it. Following a creek with no trail is often very tough, often encountering alder thickets, bogs, head high stinging nettle, steep banks etc.
To me the safest way is take a bearing a little West of point E and meander along the easiest walking to the lake at point E. Generally speaking it is much easier and safer to follow a ridge or at least stay out of a creek bottom.

While taking a bearing on E and following that bearing is technically correct, the question asks for the “safest” way to get to the lake. If there are obstacles or a lack of accuracy in taking and following that direct bearing, it would be possible to travel too far to the south and miss the lake. Aiming at a point on the creek gives a better target since you would have a good chance to run into the creek somewhere along its length. It would then be used as a “railing” to follow it upstream until reaching the lake — nothing says you have to actually follow the creek, you could move a little ways away to better terrain, as long as you know the creek is still to your right.

Regarding Question 15. Direct course from B to E. The land is as flat as can be determined with 50 ft contour intervals for most of the distance. The map color indicates the area is under tree canopy. The head of the ravine on the right along direction of travel provides a bearing check. After that just stay on course and walk down hill to the lake.
I would only recommend the creek course if one could not hold a compass bearing or interpret land features from a map; but then I would give them a tracking collar to wear with the compass.

Lots of interesting debate on needle weighting and where a compass will work. I’d like an answer from a compass manufacturer like Brunton or Silva.
Since it is the magnetic field and not a big magnet area that controls the needle, it makes me wonder.

You already have your answer from Suunto. That’s why they sell the more expensive “Global” model. That model is designed to be used all over the globe while their regular models are designed to be used in the hemisphere where they are purchased.

I googled “brunton compass south america” which gave a link to their instruction manual, wherein they ask customers to contact rhem for compasses best suited for areas in rhe southern hemisphere. I would provide a link, but I haven’t figured out how to do that on a smart phone. I did quote previously from the NOAA page, but I realize that the govetnment created that page.

As I stated in a previous post I have used my compass south of the equator( Tonga) . What I did not mention was that it was a Silva Ranger . Once again, it work just fine…
“In theory, there is no difference between theory and practice. In practice, there is.” – Unknown

“Contour lines can never cross one another. Each line represents a separate elevation, and you can’t have two different elevations at the same point. The only exception to this rule is if you have an overhanging cliff or cave where, if you drilled a hole straight down from the upper surface, you would intersect the earth’s surface at two elevations at the same X,Y coordinate. In this relatively rare case, the contour line representing the lower elevation is dashed. The only time two contour lines may merge is if there is a vertical cliff (see figure).”

While folks are focused on Question 16 which is pretty basic, as an experienced backpacker, I don’t like any of the choices for Question 15. The map shows what may be a relatively easy cross-country path to the destination lake that is both shorter and has considerably less uphill. The “official” answer has several problems. First getting to the river is not so easy; no straight line path is a good choice. Second, you lose more elevation than necessary, which must be regained. Third, creeks and rivers often don’t have good walking paths beside them, the banks being cliffs. So you may find yourself either walking in water, which if deep or swift is dangerous, or following cliffs above the water,likely up and down. Fourth, the distance of the path suggested in the “official” answer is certainly longer than the cross-country path. The missing information needed to make a good decision is terrain type. If the cross-country path is through dense brush or boulder fields, that would recommend against it. Also, at 1000 feet (or meters) elevation, you might be in poison oak/ivy habitat, another factor to consider. When traveling cross-country, groups should stay together, and at least one member needs to be skilled at map/compass orienteering. Don’t trust your life or your buddies to a battery-operated GPS.

it doesn’t matter where you are in the world or what compass you use, you must hold it so the needle swings freely. that is compass 101. also, the safest path from point b to e, according to the information given, is the one with the fewest apparent obstacles. shoot a bearing toward the lake and if the last little elevation drop presents trouble, use the box method to skirt around it…however you should be able to see the lake from that point.

I understood most of the answers (or looked up what I didn’t), except Q.5… I don’t understand it. It seems as the creek, from the lake starts out as a flood plain, and then has one small dip at the base of mountain “A.” Then it continues downstream past 2 more small dips, and into lake “E.”

It looks as if I would be paddling with the current, not against it as the answer presents. Could someone explain this answer to me, please?
Thanks.

That’s simple enough… I thought that the point of the “v” or “U” directed the slope. I was over-thinking the problem, and not paying attention to the rest of the terrain related to the contour lines. Silly question that I asked!

Hello Bo,
The big lake elevation is some under 1,000 feet elevation. Each time you cross a contour line you are 50 feet higher up, as stated in the next question. After leaving the lake at something under 1,000 feet you cross 3 more 50 foot contour lines thus putting you something over 150 feet higher in the smaller lake, so you paddled up stream.

Yep… The contour lines/ intervals was where I should have been looking. I focused only on the “v”/ “U” shape, and that is what threw me off. I’m used to thinking about these shapes in regards to hilltops/ spurs, and didn’t think about it in terms of drainage. This has been a great learning tool for me!

The answer to 2 IS correct. Remember, the 90 degree bearing was determined off the map alone. When you are in the field, the magnetic declination is 10 degrees east per the stated situation, so you must subtract that 10 degrees from the 90. If you leave your compass at 90 degrees, you will actually be headed 100 degrees from TRUE north.

I’m a leader in troop 45 Crown Point, Ind. I’d like a copy of the quiz, without all the replies. Is that possible? When I try to print this out, I get the first page and then about 10 pages of replies, frustrating.

One can select and copy the quiz questions and paste into a Word document. One can right click and copy the topo map, then paste it too. After formatting adjustments, one can print the quiz and save the document for future use. Many Scouts can do these steps better than adults.

However, on page 2 of Scouting magazine is written “Copyright 2014 by the Boy Scouts of America. All rights thereunder reserved; anything appearing in Scouting may not be reprinted either wholly or in part without written permission.”

This statement applies to the printed magazine, but the web site surely has a similar restriction. Perhaps someone who knows copyright law can explain what “fair use” law will allow. Can Scouters lawfully use material that appears in Scouting magazine?

Phillip and Steve, you’re welcome to use the quiz within your troop meetings. You may use material within Scouting magazine so long as it is NOT for commercial purposes. We’re here to serve! Hope you and your Scouts/Venturers get some value from this quiz and the others, too.

I loved this quiz. One – I got a 95% and two – I think that a beginner or and experienced person will learn something. I new knew there was a dot of paint to weight the South end of the neelde. I would just dip the compass slightly to compensate. WRT to Q #15 – I figured it was safer to head to the creek and follow the 1250 foot controur line staying just west of the Point E (approximately 240 degree) bearing. Eventually you will be close to the creek and the lake. You will also not loose or have to gain evelation. Points B and C will be triangluated. 40 degree by 70 degree. That is if you can see them. There would be a drop of 150 to 200 feet and our of vision. There is a lot to assume with this map. Nonetheless, I liked the quiz and I would like see more like this. Perhaps using a satelite image as well.

Question 16 is wrong. the answer I gave is right. You always hold a compass so the needle is level and will float freely. You always need to know what the declination is relative to where you are located at on earth. Go check this out. http://starryskies.com/articles/dln/8-97/compass.html

They are wrong in several respects. I won’t go into all of them but In the first place compasses are affected by declination and also by deviation. Deviation is such as near by metal or mineral deposits. Better take the word of a compass manufacture than a couple of theorist.
Remember the old saying, “Don’t believe anything you hear and only half of what your read”.

Terry Hairston’s answer is correct. A compass’s magnetic needle responds to local magnetic field. As such, the needle’s orientation depends on declination, deviation, and dip. Question 16 is about dip and how to compensate for it. Barring a global needle (Suunto’s fancy double hinged pivot), an ordinary needle will not be level when used outside its compass zone. It does not matter how you hold the compass. There is simply no way to hold the compass to make the needle level. So Tracy Millet’s comment about holding the compass to make the needle level makes no sense. The best you can do is to tilt the compass so the needle swings freely. This is probably what quiz author Cliff Jacobs meant to write, but he did not get the wording right on the official answer. Note the method of tilting the compass to accomodate a non-level needle only works if the dip is less than about 20 degrees. Otherwise a different problem arises – the pivot will hang up. Even Suunto’s global needle has a limited dip compensation capability. So I guess one must avoid getting too close to the poles.

Regarding Q15, I cannot agree with your answer. I read, and agree with, some posts that argue that a direct route from B to E would be best. After 28 years in the U.S. Army and many training young Soldiers in Land Nav., it only makes sense to use the shortest path with the least resistance. Humans walk in a circle without a compass (i.e. a rightie walks to the right) and navigating through more vegetation requires constant correction of course. By far easier to go direct from B to E.

Taken literally, yes, aim for the big target — the lake — and go right to it (and hope you were accurate in your bearing, didn’t run into obstacles to get off track, or just generally messed up). If you are right, and good, you should hit the lake square on.

But look at the problem generically — you are looking for a small campsite located along a trail. You might be good enough to go directly to the campsite, or you might not. Aiming for a point on the trail (which in comparison is “larger” than one specific point) at least puts you in the vicinity of where you want to be — then all you have to do when you hit the trail (assuming it is a beaten path and not some game trail not easily seen) is decide whether to turn right or left to head to the campsite.

Part of teaching Scouts (and others) is getting them to learn how to solve problems with knowledge you are passing on or that they have already learned. Telling them “take a bearing and go directly to that point” isn’t incorrect, but it is shortchanging them on other tools they can use to navigate in all terrain and conditions.